It seems there is an issue with Lync 2013 KB2760556 March Update which causes desktop sharing to fail. We have also noticed that somehow KB2760556 ends up installed twice on some machines, possibly installed once manually, then installed again by windows update. In some situations it has reappeared twice even after being removed.

You can quickly check for duplicate install issue in PowerShell,

Get-HotFix | Where-Object {$_.HotFixID -like “*556*”}

It seems if you uninstall KB2760556 (twice if you need to as above), reboot then reinstall it works, or sometimes uninstall KB2760556 then reinstall February Update KB2760512 then KB2760556

Others have reported the issue and other combos of uninstalling and reinstalling the patch have worked for them:

Tom Arbuthnot is a Microsoft Lync Certified Master and MVP. He is a blogger, regular on The UC Architects Podcast, contributing writer to Lync Server 2013 Unleashed and speaker at events such as Lync Conference and The Microsoft UC User Group London. He is currently Managing Consultant at Modality Systems.

I have tried the above suggest as well as others. It appears that the problem is hit or miss with most of the computers I am installing Lync on. Unfortunately, I don’t show the 2760556 update in my list. I am in the process of approving the 2760512 to see if this resolves the issue. Hopefully I will have good news for you after. I am also experiencing an issue after installation and have a support ticket open with Microsoft for that. Do you take requests? ;)